Pressure Loss owing to multiple nozzles

AI Thread Summary
The discussion focuses on calculating pump discharge pressure in a system with multiple nozzles. The approach involves determining pressure loss due to flow through a horizontal pipe and the cumulative pressure loss from 110 nozzles, each exerting 100 psi. Key calculations include finding the Reynolds number to assess flow type, determining relative roughness, and calculating the friction factor using Moody’s chart or the Colebrook equation. The total pressure loss is then converted to Pascal units and used to compute wattage based on flow rate. The methodology is presented as a systematic approach to ensure accurate results in pressure loss calculations.
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The following is the advancement of what I discussed in the link https://www.physicsforums.com/showthread.php?p=4274966#post4274966

Problem Statement
To calculate Pump Discharge Pressure, Calculate the wattage for the pump

Data :
  • Water @ 85 Degree C
  • Flow in for 24” pipe : 3010 m^3/hr
  • Flow in 8” pipe : 405 m^3/hr
  • Total length of pipe = 50ft
  • Nozzle Dia : 1"
  • Nozzle pressure : 100 psi
  • Nozzle Gallons per minute = 119
  • Number of Nozzles = 110 (placed equidistant along the length of the pipe)
  • Kinematic & Dynamic Viscosity of water can be found on : http://www.engineeringtoolbox.com/water-dynamic-kinematic-viscosity-d_596.html


Is my approach (mentioned below) correct ?
Pump Discharge Pressure = Pressure Loss owing to flow thru Horizontal Pipe + Nozzle Pressure* Number of Nozzles
Then,

  • Find Reynolds Number
  • Determine if its turbulent or laminar flow?
  • Find the relative roughness of the pipe
  • Find the friction factor, either from Moody’s chart or Colebrook equation
  • Then calculate pressure loss = (fρLV^2)/(D*2) in Pascal


Now calculating Nozzle Pressure ,
  • Already given that per nozzle 100 psi. So total pressure loss owing to nozzles; is 100*110 and convert to Pascal units.

Then add ;
  • pressure loss (calculated above) with the Pressure loss owing to those 110 Numbers of nozzles...
    and, use the above addition and multiply with the flow rate to attain the wattage ?


Is this approach Correct ? Am I missing something ?
 
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